Use Q_CC_{GNU,MSVC}_ONLY when comparing to particular versions

This prevents false-negatives and false-positives, as e.g. Clang
10.0.0 masks as GCC 4.2, so Q_CC_GNU is 402 on that
compiler. Depending on the test (Q_CC_GNU > NNN or Q_CC_GNU < NNN),
the result of the test is almost random.

Q_CC_<comp>_ONLY makes sure we match only GCC or MSVC, not bycatch
such as Clang or ICC.

Pick-to: 6.3 6.2 5.15
Change-Id: I4c550a11ecf85fc9a2216b330b69bd03d45b47e0
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

7 files changed, 8 insertions, 8 deletions

diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h
index b3479de309..f7989da8be 100644
--- a/src/corelib/global/qcompilerdetection.h
+++ b/src/corelib/global/qcompilerdetection.h
@@ -1353,7 +1353,7 @@
 #endif
 #endif
 #ifndef Q_FALLTHROUGH
-#  if (defined(Q_CC_GNU) && Q_CC_GNU >= 700) && !defined(Q_CC_INTEL)
+#  if defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 700
 #    define Q_FALLTHROUGH() __attribute__((fallthrough))
 #  else
 #    define Q_FALLTHROUGH() (void)0
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 5de3c780c3..82a33939dc 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -1189,7 +1189,7 @@ constexpr std::underlying_type_t<Enum> qToUnderlying(Enum e) noexcept
 # endif
 #elif defined(__has_cpp_attribute) && __has_cpp_attribute(clang::require_constant_initialization)
 # define Q_CONSTINIT [[clang::require_constant_initialization]]
-#elif defined(Q_CC_GNU) && Q_CC_GNU >= 1000
+#elif defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 1000
 # define Q_CONSTINIT __constinit
 #else
 # define Q_CONSTINIT
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 8b52752470..58bbb5f813 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -2204,7 +2204,7 @@ constexpr auto typenameHelper()
         constexpr int suffix = sizeof("]");
 #endif
 
-#if (defined(Q_CC_GNU) && !defined(Q_CC_INTEL) && !defined(Q_CC_CLANG) && Q_CC_GNU < 804)
+#if defined(Q_CC_GNU_ONLY) && Q_CC_GNU_ONLY < 804
         auto func = Q_FUNC_INFO;
         const char *begin = func + prefix;
         const char *end = func + sizeof(Q_FUNC_INFO) - suffix;
diff --git a/src/corelib/text/qbytearrayalgorithms.h b/src/corelib/text/qbytearrayalgorithms.h
index 164868fa91..ae48215850 100644
--- a/src/corelib/text/qbytearrayalgorithms.h
+++ b/src/corelib/text/qbytearrayalgorithms.h
@@ -134,7 +134,7 @@ Q_CORE_EXPORT char *qstrdup(const char *);
 inline size_t qstrlen(const char *str)
 {
     QT_WARNING_PUSH
-#if defined(Q_CC_GNU) && Q_CC_GNU >= 900 && Q_CC_GNU < 1000
+#if defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 900 && Q_CC_GNU < 1000
     // spurious compiler warning (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91490#c6)
     // when Q_DECLARE_METATYPE_TEMPLATE_1ARG is used
     QT_WARNING_DISABLE_GCC("-Wstringop-overflow")
diff --git a/src/corelib/text/qlocale.cpp b/src/corelib/text/qlocale.cpp
index 47848fa80c..faf9fd8c82 100644
--- a/src/corelib/text/qlocale.cpp
+++ b/src/corelib/text/qlocale.cpp
@@ -40,7 +40,7 @@
 
 #include "qglobal.h"
 
-#if (defined(QT_STATIC) || defined(QT_BOOTSTRAPPED)) && defined(Q_CC_GNU) && Q_CC_GNU >= 1000
+#if (defined(QT_STATIC) || defined(QT_BOOTSTRAPPED)) && defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 1000
 QT_WARNING_DISABLE_GCC("-Wfree-nonheap-object") // false positive tracking
 #endif
 
diff --git a/src/corelib/tools/qhash.cpp b/src/corelib/tools/qhash.cpp
index 24e710c2e5..8c1c3a8d13 100644
--- a/src/corelib/tools/qhash.cpp
+++ b/src/corelib/tools/qhash.cpp
@@ -382,7 +382,7 @@ static uint64_t siphash(const uint8_t *in, uint64_t inlen, uint64_t seed, uint64
     }
 
 
-#if defined(Q_CC_GNU) && Q_CC_GNU >= 700
+#if defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 700
     QT_WARNING_DISABLE_GCC("-Wimplicit-fallthrough")
 #endif
     switch (left) {
@@ -486,7 +486,7 @@ static uint siphash(const uint8_t *in, uint inlen, uint seed, uint seed2)
         v0 ^= m;
     }
 
-#if defined(Q_CC_GNU) && Q_CC_GNU >= 700
+#if defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 700
     QT_WARNING_DISABLE_GCC("-Wimplicit-fallthrough")
 #endif
     switch (left) {
diff --git a/src/corelib/tools/qoffsetstringarray_p.h b/src/corelib/tools/qoffsetstringarray_p.h
index 3e4abf4bb5..6287edf761 100644
--- a/src/corelib/tools/qoffsetstringarray_p.h
+++ b/src/corelib/tools/qoffsetstringarray_p.h
@@ -66,7 +66,7 @@ class tst_QOffsetStringArray;
 QT_BEGIN_NAMESPACE
 
 QT_WARNING_PUSH
-#if defined(Q_CC_GNU) && Q_CC_GNU >= 1100
+#if defined(Q_CC_GNU_ONLY) && Q_CC_GNU >= 1100
 // we usually don't overread, but GCC has a false positive
 QT_WARNING_DISABLE_GCC("-Wstringop-overread")
 #endif